# CVE-2026-101058: python-utcp server-side request forgery via remote HTTP manual

Source: https://junglewise.ai/threats/cve-2026-101058-python-utcp-pip-package-utcp-http-before-1-1-12-does-not-verify  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-27. Updated: 2026-09-27  
License: CC BY 4.0 with a link back

CVE-2026-101058 · Severity: medium · CVSS 6.9 · Published 2026-09-27

python-utcp is a library that allows applications to discover and invoke tools through UTCP manuals. When a client fetches a tool manual from a remote server, the library failed to validate that tool URLs don't point to the victim's own loopback address (127.0.0.1), allowing an attacker to redirect tool calls to local services. An attacker who can serve a malicious manual can cause the client to access internal services and leak their responses back to the attacker.

Technologies: [Universal Tool Calling Protocol Python-Utcp](https://junglewise.ai/threats/technologies/python-utcp). Vendors: [Universal Tool Calling Protocol](https://junglewise.ai/threats/vendors/universal-tool-calling-protocol).

## Quick answers

**Is CVE-2026-101058 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101058 being exploited in the wild.

**How severe is CVE-2026-101058?** Medium severity, with a CVSS score of 6.9, published 27 September 2026.

**Which products and versions are affected?** Universal Tool Calling Protocol Python-Utcp before 1.1.12.

**Is there a fix for CVE-2026-101058?** A patch was published on 2026-09-27: Version 1.1.12 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-101058 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-101058?** Check whether you run Universal Tool Calling Protocol Python-Utcp at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a server-side request forgery (SSRF) in the http, sse, and streamable_http protocol handlers. When discovering UTCP manuals from non-loopback origins, the library failed to reject tool URLs pointing to loopback addresses, despite having such checks in the OpenAPI converter path. Native manuals bypass the OpenAPI converter's loopback validation. Exploitation requires the attacker to serve a malicious UTCP manual that the victim registers, and further requires an unauthenticated loopback service on the victim host that returns useful data.

## Affected products

- Universal Tool Calling Protocol python-utcp before 1.1.12

## Timeline

- 2026-09-05: disclosed: GitHub security advisory published
- 2026-09-27: patched: Version 1.1.12 released with fix

## References

- [https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8vxx-v7r9-948g](https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-8vxx-v7r9-948g)
- [https://www.vulncheck.com/advisories/python-utcp-before-1.1.12-ssrf-via-remote-http-manual](https://www.vulncheck.com/advisories/python-utcp-before-1.1.12-ssrf-via-remote-http-manual)

## Related threats

- [python-utcp server-side request forgery via unvalidated HTTP redirects](https://junglewise.ai/threats/cve-2026-101060-python-utcp-versions-before-1-1-4-contain-a-server-side-request)
- [python-utcp localhost prefix validation bypass in utcp-gql and utcp-websocket](https://junglewise.ai/threats/python-utcp-localhost-prefix-validation-bypass-in-utcp-gql-and-utcp-cca0bdf1)
- [Universal Tool Calling Protocol SSRF via localhost validation bypass](https://junglewise.ai/threats/cve-2026-12210-universal-tool-calling-protocol-ssrf-via-localhost-validation)
- [python-utcp OS command injection in CLI communication protocol](https://junglewise.ai/threats/cve-2026-45369-python-utcp-os-command-injection-in-cli-communication-protocol)